PROJECT SUMMARY Antiretroviral therapy (ART) adherence and retention in care are critically important and poorly understood challenges in the care of women living with HIV in the United States. Postpartum attrition and ART non- adherence leave women with HIV at risk for life-threatening medical complications of immunocompromise and unplanned and not-medically-optimized pregnancies with greater risk of mother-to-child transmission. The long-term objective of this proposal is to improve adherence and retention in care for women living with HIV. To achieve this objective, we propose a prospective, cohort study of women with HIV during pregnancy and postpartum to 1) adapt an objective ART adherence measure in each trimester and postpartum, 2) characterize the behavioral health predictors of postpartum ART adherence and retention in care, and 3) inform the feasibility and design of future research on behavioral health interventions to improve adherence and retention in care. Our proposal's goals match the National Institute of Mental Health Division of AIDS Research high research priority ?to develop and test interventions to improve HIV treatment outcomes through optimal treatment adherence and sustained engagement in care?. Our specific aims are to: 1: Adapt and apply the TDF adherence instrument in each trimester of pregnancy and postpartum and test the hypothesis that adherence concentration benchmarks will be lower in the 2nd and 3rd trimesters of pregnancy and immediately postpartum, normalizing in the postpartum period. 2: Test the hypothesis that trauma-related behavioral health indicators are predictive of postpartum adherence and retention in care, through administration of a battery of behavioral health measures (depression, PTSD, anxiety) during pregnancy and examining associations with postpartum adherence and retention in care. My long-term career goal is to establish an interdisciplinary independent research career focused on improving the medical care and clinical outcomes of women living with HIV during pregnancy and beyond. The training aspect of the grant will focus on a combination of didactic course work and experiential learning to achieve my career development objectives: expertise in 1) pharmacology, namely pharmacokinetic research and data analysis, and 2) behavioral health, specifically mental health topics pertaining to trauma, HIV and pregnancy/postpartum, and 3) implementation of clinical and behavioral health randomized controlled trials. The academic environment, institutional support, and exceptional resources collectively provided by the Mid- Atlantic CFAR consortium, MedStar Health, and Johns Hopkins University provide an ideal opportunity for growth as an investigator. This integrated, comprehensive combination of research experience combined with intensive mentoring, didactic coursework, and participation in a community of learners will directly advance my career development objectives and provide me with the necessary tools and experience to transition to a successful, interdisciplinary, independent clinical researcher.